Dalton, who owns the South Coast Legal Services constable business, changed careers in 2001 after 16 years as a Plymouth County deputy sheriff. But he didn't go willingly.

He and two other cashiered deputies filed a federal lawsuit claiming they had been unjustly fired. At the trial, the county introduced evidence from a State Police investigation in 2000 that Dalton had allegedly sought cash payments from a Brockton moving company trying to obtain county work in court-ordered eviction cases.

The federal jury upheld the dismissals. In an interview, the 60-year-old Dalton said the allegations were false but refused to discuss the issue further. He was never charged criminally in the case.

As for the $625 fee he charges for each car seizure, Dalton was hardly defensive about his price; he said he is considering an increase to offset the higher cost of gasoline. ''I have a lot of guys burning up gas, looking for cars,'' he said.

State law requires cities and towns to ''investigate the reputation and character '' of all constable applicants, as well as their fitness for office. But the law sets no specific criteria. In some communities, a police criminal background check is required. But in some cases the background checks appear to be cursory.

In Boston, police do background checks before Menino appoints constables. But Dorsey, the constable who demanded $1,250 for seizing Fitzpatrick's car, was appointed by Menino even though he listed his criminal record on his application. On Super Bowl Sunday in 1994, according to court records, Boston police raided the Old Stag Tavern in Jamaica Plain, which Dorsey managed, arrested Dorsey for running a betting operation and

confiscated the two firearms. He was found guilty of a misdemeanor for possessing gaming materials and was fined $300. Dorsey, who is 50, also had a prior arrest for failure to make child support payments.

Boston Police Sergeant Raymond Mosher, who oversees criminal background checks for prospective constables, said he could not discuss Dorsey's case because of privacy restrictions.

Like Sorenson, both Dalton and Dorsey have had financial struggles not unlike those of some of the debtors whose cars they seize. A decade ago, Dalton had one small-claims judgment and two federal tax liens against him, according to court records reviewed by the Globe. And Dorsey says his own struggles help him empathize with the people who are his quarry.